Cutter trimmer sorter

ABSTRACT

An apparatus for cutting and sorting boards conveys the boards along a conveyor path. The apparatus senses the length of boards and the grade of boards, and cuts selected boards into first and second segments. The first and second segments are aligned against lumber lines respectively on each side of a conveyor path. The boards are then selectively sorted and dropped into bins successively positioned along each side of the conveyor path.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of prior U.S. patentapplication Ser. No. 10/108,216 filed Mar. 26, 2002 now U.S. Pat. No.6,826,990, the benefit of the priority of which is hereby claimed under35 U.S.C. §120.

FIELD OF THE INVENTION

The present invention relates to cutting and sorting of boards in asawmill and planermill operation and, more particularly, to an automatedsystem for cutting, trimming, and sorting boards into a plurality ofreceiving bins in an efficient manner.

BACKGROUND OF THE INVENTION

After rough sawn boards are produced in a sawmill, they are commonly runthrough a plurality of planing, grading, trimming, cutting, and sortingoperations. In current cutting, trimming, sorting operations, aplurality of boards of various lengths, up to 20 ft. long, for example,are fed by a conveyor along a predetermined path in a machine direction.The boards are oriented orthogonally to the machine direction. Theconveyor has lugs that advance the board through a sensing station. Atthe sensing station, shape properties of the board are determined,including length, width, wane (missing wood due to circular shape of thetree), crook and bow. These shape parameters are evaluated along thelength of each board to determine the grade of various portions of theboard. The board advances in front of a human operator who will makevisual based grade decisions based on quality parameters that cannot bedetermined by the sensing station. The information from the sensingstation and the human operator are sent to a programmable logiccontroller, where the data is analyzed to determine the optimal gradeand length solution for the individual board. The programmable logiccontroller controls a plurality of saws that are spaced laterally acrossthe conveyor at a sawing station. Depending upon the length and gradeinformation, the board can either pass under the saws without being cut,or it can be cut at a predetermined location along the length of theboard, depending upon the information received by the programmable logiccontroller from the sensing station and from the human operator.

After boards pass the sawing station, the boards pass over a pluralityof aligning rollers. These rollers are oriented parallel to the machinedirection and rotated in a clockwise direction looking in the machinedirection. As the boards pass over these rollers, they are moved to theright looking in the machine direction, until their ends abut a railrunning parallel to the right-hand side of the conveyor, normallyreferred to as a lumber line. If a board has been split in two segments,the programmable logic controller will leave an extra space on theconveyor so that the second segments of the board, which occupied onespace on the conveyor when being cut, is now indexed so that it occupiesa successive location on the conveyor. The second segments of the cutboards are also aligned against the right-hand lumber line.

Downstream from the aligning rollers lie a plurality of receiving bins.The receiving bins are positioned under the conveyor in a conventionalmanner. The programmable logic controller operates drop gates on theconveyor so that boards of common length and grade are dropped intopredetermined bins. In this manner, a single bin receives boards of asingle length and grade. The bins are periodically emptied and theboards subsequently stacked for shipment in a conventional manner.

Because each of the boards, whether a single uncut board or a board thathas been cut in two, occupy one station on the conveyor downstream ofthe saws, the actual throughput of the cutter trimmer is reduced by thenumber of boards that are cut in two because the second segment mustalso be indexed against the right-hand lumber line. For example, if 10%of the boards are cut in two, then the actual throughput from themachine is reduced by 10%, relative to the number of boards that can befed into the machine. It is therefore desirable to provide a method andapparatus for increasing the efficiency of the cutter-sorter of the typejust described.

SUMMARY OF THE INVENTION

The present invention therefore provides an apparatus for cutting andsorting boards into variable lengths. A conveyor is provided to conveyboards along a predetermined path in a machine direction. A sensor ispositioned along the path for determining the shape parameters of theboard, including length, width, wane, crook and bow. These shapeparameters are evaluated along the length of each board to determine thegrade of various portions of the board. The board advances in front of ahuman operator who will make visual-based grade decisions based onquality parameters that cannot be determined by the sensing station. Theinformation from the sensing station and the human operator are sent toa programmable logic controller, where the data is analyzed to determinethe optimal grade and length solution for the individual board. Aprogrammable logic controller receives the length and grade signals anddetermines whether, and at what location along the length of the board,it will be cut into two segments. A saw is positioned along the pathdownstream from the sensor. The saw is controlled by the controller forcutting the board at the cutting location. Downstream of the saw, afirst lumber line is provided adjacent the right side of the path and asecond lumber line is provided adjacent the left side of the path. Afirst lateral conveyor is provided for moving boards laterally towardthe right side of the path so that the right ends of the boards adjacentthe right side of the conveyor abut and are aligned with the firstlumber line. A second lateral conveyor is provided for moving boardslaterally toward the left side of the path so that the left ends of theboards adjacent the left side of the conveyor abut and are aligned withthe second lumber line. Thereafter, a first plurality of bins aresuccessively positioned under the right side of the conveyor path forselectively receiving boards of predetermined length and grade alignedagainst the first lumber line. A second plurality of bins aresuccessively positioned adjacent the left side of the conveyor path forselectively receiving boards of predetermined length and grade that arealigned with the second lumber line.

A method of sawing and trimming boards comprises a plurality of stepsincluding (a) feeding a plurality of boards past a sensing station on aconveyor; (b) sensing the length (and optionally the grade) of eachboard; (c) determining whether and at what location the board will besawn; (d) sawing the board at the location; (e) aligning boards adjacentone side of said conveyor against a lumber line on that one side; (f)aligning boards adjacent the other side of said conveyor against alumber line on that other side; (g) selectively placing boards adjacentthe lumber line on the one side into a plurality of bins successivelypositioned adjacent the one side; and (h) selectively placing boardsadjacent said other side in a plurality of bins successively positionedadjacent the other side.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic plan view of a cutter sorter constructed inaccordance with the present invention;

FIG. 2 is a schematic elevation view corresponding to FIG. 1;

FIG. 3 is an enlarged plan view of a portion of a lateral conveyor andthe positioning skids associated therewith; and

FIG. 4 is an enlarged elevation view of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1 and 2, the cutter sorter 10 includes a conveyor12 comprising a plurality of conveyor chains 12 a-12 k that are alignedin parallel runs. Only the upper portion of the runs are shown in FIGS.1 and 2 for simplicity. The conveyor moves in a machine directionindicated by arrows 14. Each of the conveyor's chains 12 a-12 k carryupstanding lugs 16 a-16 k. The lugs 16 a-16 k are aligned laterallyacross the conveyor chains 12 a-12 k and are positioned at successivelocations along the length of the conveyor chains 12 a-12 k. Each of thesets of lugs 16 a-16 k are spaced by the distance slightly greater thanthe width of the boards to be handled by the conveyor.

Boards, for example, board 18, are positioned on the conveyor 12 and aremoved in the machine direction 14 via the conveyor chains 12 a-12 k andlugs 16 a-16 k. The boards may have various lengths ranging, forexample, from 8 ft. to 20 ft. although, these lengths will depend uponthe lumber produced by the sawmill, the trimming operations and thedemands of the marketplace for various lengths of boards. The conveyor12 moves each board past a sensing station where an optical sensor 20scans the board and generates a signal indicative of the overall lengthof the board. Alternatively, the board may be scanned in thelongitudinal direction prior to being placed on the conveyor. Theoptical sensor may also be employed to scan the shape of the boards andgenerate a signal indicative of the grade of the board, for example,whether the board has varying amounts of wane at various locations alongthe length of the board. In addition to the optical sensor, the board isgraded by a human operator for visual defects the optical sensor cannotdetect.

The sensing station provides a length and grading signal to aprogrammable logic controller 21. The programmable logic controller 21also receives input from a human operator as to the most preferredlengths and grades of boards to be produced at a given time by thecutter sorter 10. This information is then processed by the programmablelogic controller 21 to determine whether and at what location along itslength a given board will be sawn. The boards are then conveyed to asawing station. For example, board 22 is positioned under a plurality ofrotary saws 24 a-24 jat the sawing station. The saws 24 a-24 j arepositioned at laterally spaced locations along the conveyor 12 betweeneach of the successive chains 12 a-12 k. The saws 24 a-24 jare mountedso as to be vertically moveable into and out of the path of the board 22as it traverses under the saw station. The logic controller 21 sends apredetermined signal to the saw controller 26, providing information tolower the appropriate saw and cut board 22 at a predetermined locationalong its length. As shown in FIGS. 1 and 2, saw 24 f has been loweredby the saw controller 26 so as to cut the board 22 into two equallengths. The same operation has already been performed on board 30downstream of the sawing station.

Stationary rails, commonly referred to as lumber lines, are providedalong each side of the conveyor. The right-hand lumber line 32 ispositioned longitudinally along the right-hand side of the conveyor 12looking in the machine direction while a left-hand lumber line 34extends longitudinally along the left-hand side of the conveyor 12. Therails are positioned at a level slightly above the upper surface of theconveyor 12. The lumber lines 32 and 34 are only shown in FIG. 1 and areomitted from FIG. 2 for simplicity.

Downstream from the sawing station, a plurality of aligning conveyorrollers 40 have their axes aligned parallel to the machine direction 14and are positioned between successive runs of the conveyor chains 12a-12 k. The upper surface of the rollers 40, as shown in FIGS. 3 and 4,are positioned slightly above the upper surface of the conveyor chains12 a-12 k. The rollers 40 are mounted for rotation by conventional meansnot shown, to rotate in a clockwise direction looking in the machinedirection 14. As successive boards, for example boards 44 a and 46 a,pass over the aligning rollers 40, they will be moved laterally in aright-hand direction as indicated by arrow 50. The boards 44 a and 46 awill be moved laterally until the right-hand ends of the boards 44 a and46 a abut the rail comprising the right-hand lumber line 32.

Referring to FIGS. 3 and 4, the left-hand board segments 44 b and 46 b,corresponding to right-hand segments 44 a and 46 b, are shown being heldin a position above the rollers 40 by a plurality of positioning skids52 as they pass over aligning rollers 40. The positioning skids 52 arepositioned in a conventional manner between the left hand portion ofrollers 40. The positioning skids are mounted by conventional means formovement in a vertical direction in response to signals from thepositioning skid controller 54, at the appropriate time. For example, asboards 44 a and 4 b are being moved to the right by aligning rollers 40,positioning skids are raised by the controller 54 so as to raisesegments 44 b and 46 b above the rollers 40. Thus board segments 44 band 46 b remain laterally stationary as they traverse over theright-hand aligning rollers 40. When, for example, a longer board, suchas board 58, traversed the right-hand aligning rollers 40, thepositioning skids 52 are lowered to the position shown in phantom inFIG. 4 as board 58 passed over the positioning skids so all of therollers 40 could have effectively functioned to move the board 58laterally against the right-hand lumber line 32.

A second set of aligning rollers 60 are positioned downstream from theright-hand aligning rollers 40 between the runs of chains 12 a-12 e andadjacent the left-hand side of the conveyor 12. Aligning rollers 60 arerotated in a counterclockwise direction looking in the machine direction14. As boards, for example, board segments 62 b and 64 b, pass over therollers 60, they will be moved laterally in a left-hand direction asindicated by arrow 68 toward left-hand lumber line 34 until their leftends abut against the left-hand lumber line 34. Thus, the left-handsegments of boards 62 b and 64 b are aligned to the left-hand lumberline 34 so that they can be sorted separately from the right-handportions of the boards 62 a and 64 a. Positioning skids 66 arepositioned between the aligning rollers 60. The skids 66 are in thedownward position (corresponding to the position of skid 52 shown inFIG. 4 for the right-hand aligning skids) when boards pass thereover tobe aligned to the left-hand lumber line 34. However, as board 58, forexample, passes over the left-hand aligning rollers 60, the positioningskids 66 will be raised so that the left-hand aligning rollers 60 willnot contact the board 58 and move it away from its alignment with theright-hand lumber line 32.

A plurality of right-hand lumber bins 80, 82, 84, 86, 88, 90, and 92 arepositioned below the upper run of the conveyor 12 and have theirright-hand ends aligned with the right-hand lumber line 32. These bins80-92 are shown for purposes of illustration as corresponding to lumberlengths of 8 ft. to 20 ft., respectively. Fewer or more bins may beemployed, as needed or desired. Also, if four grades of wood are beingsorted, each of the bins 80-92 would have three corresponding partnersfor receiving the other three grades of boards of the same length. Forexample, there might be four bins for 8 ft. lengths of lumber, one forthe highest grade of lumber, one for the second grade of lumber, anotherfor the third grade of lumber, and a fourth bin containing the lowestlumber grade. For purposes of simplicity in illustration, however, onlyone bin has been shown for each length of wood. These bins 80-92 are forreceiving the various lengths of lumber aligned with the right-handlumber line 32. A drop gate controller 70 of conventional designreceives control signals from the logic controller 21 and controls dropgates 72 on each of the conveyor chains 12 a-12 k so as to drop 8 ft.lengths of lumber, for example, into bin 80 and 14 ft. lengths of lumberinto bin 86. The drop gates on the right-hand side are of conventionaldesign but are modified to drop boards only into the right-hand bins 80to 92.

Positioned adjacent the left-hand side of the conveyor 12 are additionalbins 100, 102, and 104. These bins 100, 102, and 104 have their leftends aligned with the left-hand lumber line 34 and are positioned toreceive various lengths of lumber aligned with the left-hand lumber line34. For example, in the illustration, bin 100 is sized to receive 12 ft.lengths of lumber, bin 102, 10 ft. lengths, and bin 104, 8 ft. lengths.Similarly to bins 80-92, bins 100-104 may have counterparts forreceiving the different grades of lumber as desired. Drop gates (notshown) controlled by drop gate controller 70 drop the lumber into bins100 to 104 based on control signals transmitted from the logiccontroller 21 to the drop gate controller 70. The drop gates on theleft-hand side are of conventional design, but modified only to dropboards into the left-hand bins 100 to 104.

By adding the left-hand lumber line 34, aligning rolls 60 withpositioning skids 52 and 66, and bins 100 to 104, the need to index andalign left-hand board segments to the right-hand lumber line iseliminated. In this manner, the machine throughput can be maximized toat or near 100% of the theoretical maximum. In large sawmills, thisefficiency increase can result in savings on the order of severalmillion dollars per year.

While the preferred embodiment of the invention has been illustrated anddescribed, it will be appreciated that various changes can be madetherein without departing from the spirit and scope of the invention.

1. A method of sawing and trimming boards comprising: feeding aplurality of boards past a sensing station on a conveyor along the path;sensing the length of each of said boards; determining whether aselected board will be sawn and the location at which said board will besawn based upon the sensed length; sawing the boards at said location;aligning boards adjacent one side of said conveyor against a lumber lineon said one side wherein the lumber line is contiguous with the path;aligning boards adjacent the other side of conveyor against a lumberline on said other side wherein the lumber line is contiguous with thepath; selectively placing boards adjacent said lumber line on said oneside into a first plurality of bins successively positioned along saidpath; and selectively placing boards positioned adjacent said lumberline on said other side into a second plurality of bins successivelypositioned along said path.
 2. The method of claim 1, furthercomprising: sorting said boards by length and placing boards of commonlength into predetermined ones of said bins.
 3. The method of claim 1,further comprising: determining the grade of said boards; sorting saidboards according to grade; and placing boards of common grade intopredetermined ones of said bins.
 4. The method of claim 1, furthercomprising: sensing the shape of each of the boards; and sorting theboards depending upon the sensed shape.